This is a multi-national, prospective, open-label, randomized two-arm study designed to campare the antiviral activity and tolerability of didanosine EC (ddI EC) (dosed once daily) in combination with d4T (Stavudine) and nelfinavir (NLF) with that of the combination of Combivir and nelfinavir in HIV infected subjects who have received limited or no other antiretroviral therapy, have a CD4 cell count > 200 cells per mm3, and who have a plasma viral load of > 2000 HIV RNA copied/mL, within three weeks prior to randomization. Approximately 700 subjects will be accrued in a 1:1 ration for the ddI EC/dT4/NLF and Cmobivir/NLF regimens, respectively, with the randomization stratified according to plasma HIV RNA level (<30,000c/mL;>30,000c/mL) and investigational site. Dosing will be for a period of at least 48 weeks after enrollment of the last subject.